Power take-off (PTO) assembly with a disconnect clutch

Abstract

Systems and methods for a power take-off (PTO) assembly. The PTO assembly, in one example, couples to a shaft and is driven by rotation of the shaft. The PTO assembly includes a disconnect clutch that selectively couples a bi-directional pump to the shaft. The disconnect clutch is passively actuated based on hydraulic system pressure to disengage the disconnect clutch when a prime mover is in operation and engage the disconnect clutch when the prime mover is shut down.

The invention claimed is: 
     
       1. A power take-off (PTO) assembly, comprising:
 a bi-directional pump in fluidic communication with a fluid reservoir and a hydraulic system; 
 a passively actuated disconnect clutch configured to mechanically disconnect the bi-directional pump from a transmission when a prime mover is in operation and mechanically connect the bi-directional pump to the transmission when the prime mover is shut down; and 
 a hydraulically actuated valve that is in fluidic communication with a hydraulic actuator of the passively actuated disconnect clutch. 
 
     
     
       2. The PTO assembly of  claim 1 , wherein the passively actuated disconnect clutch includes a first toothed face that is coupled to a first gear that meshes with a second gear that is coupled to an output shaft that includes an output interface. 
     
     
       3. The PTO assembly of  claim 2 , wherein the passively actuated disconnect clutch includes a second toothed face that is coupled to a shaft in the bi-directional pump. 
     
     
       4. The PTO assembly of  claim 1 , wherein the hydraulically actuated valve includes an actuation line that is hydraulically coupled to an outlet line of the bi-directional pump. 
     
     
       5. The PTO assembly of  claim 4 , wherein the outlet line is in fluidic communication with one or more lubricated components. 
     
     
       6. The PTO assembly of  claim 4 , wherein:
 when a pressure of a fluid in the actuation line is above a threshold pressure, the hydraulically actuated valve permits pressurized fluid flow to the passively actuated disconnect clutch and disengage the passively actuated disconnect clutch; and 
 when the pressure of the fluid in the actuation line is below a threshold pressure, the hydraulically actuated valve inhibits pressurized fluid flow to the passively actuated disconnect clutch and engage the passively actuated disconnect clutch. 
 
     
     
       7. The PTO assembly of  claim 1 , further comprising a first pair of check valves in fluidic communication with a first port of the bi-directional pump. 
     
     
       8. The PTO assembly of  claim 7 , further comprising a second pair of check valves in fluidic communication with a second port of the bi-directional pump. 
     
     
       9. The PTO assembly of  claim 1 , wherein the prime mover is an internal combustion engine. 
     
     
       10. The PTO assembly of  claim 1 , wherein the prime mover is an electric motor. 
     
     
       11. The PTO assembly of  claim 1 , wherein the transmission is a multi-speed transmission that includes two or more clutches. 
     
     
       12. The PTO assembly of  claim 1 , wherein a fluid in the fluid reservoir is oil. 
     
     
       13. A method, comprising:
 during prime mover operation, directing fluid from a hydraulic system to a disconnect clutch to sustain disengagement or initiate disengagement of the disconnect clutch and inhibit mechanical power transfer between a transmission and a bi-directional pump that is in fluidic communication with the hydraulic system; and 
 during prime mover shutdown, inhibiting fluid delivery to the disconnect clutch to transition the disconnect clutch into an engaged position that permits mechanical power transfer between the transmission and the bi-directional pump. 
 
     
     
       14. The method of  claim 13 , wherein mechanical power is transferred from an output shaft of the transmission to the bi-directional pump. 
     
     
       15. The method of  claim 13 , further comprising, during a transition from the engaged position to a disengaged position of the disconnect clutch, sustaining engagement of the disconnect clutch until a pump causes a fluid pressure in an actuation line to rise above a threshold value and a hydraulically actuated valve permits fluid flow to the disconnect clutch. 
     
     
       16. A power take-off (PTO) assembly, comprising:
 a bi-directional pump in fluidic communication with a sump and a hydraulic system for a multi-speed transmission; 
 a hydraulically actuated dog clutch that mechanically connects and disconnects the multi-speed transmission from the bi-directional pump; and 
 a hydraulically actuated valve that permits and inhibits oil flow to an actuation piston in the hydraulically actuated dog clutch; 
 wherein, when the hydraulically actuated valve is open and permitting oil flow that is above a threshold pressure to the actuation piston, the actuation piston disengages the hydraulically actuated dog clutch; and 
 wherein, when the hydraulically actuated valve is closed and inhibiting oil flow to the actuation piston, the actuation piston engages the hydraulically actuated dog clutch. 
 
     
     
       17. The PTO assembly of  claim 16 , wherein the hydraulically actuated valve is actuated via an actuation line that is in fluidic communication with the hydraulic system. 
     
     
       18. The PTO assembly of  claim 17 , wherein the hydraulic system includes a pump that is driven by a prime mover. 
     
     
       19. The PTO assembly of  claim 18 , wherein the prime mover is a traction motor.